JP2023023338A - Manufacturing method of molding and molding device - Google Patents

Abstract

To provide a technology for suppressing a decrease in strength of a molding in a manufacturing method of a molding.SOLUTION: A manufacturing method of a molding comprises a first step of forming a first molding layer on a base material by melting and solidifying a first metal powder, a second step of heating the first molding layer, and a third step of forming a second molding layer having a smaller coefficient of thermal expansion than the first molding layer. The third step forms the second molding layer on the heated first molding layer by melting and solidifying a second metal powder.SELECTED DRAWING: Figure 2

Description

The present invention relates to a manufacturing method of a modeled body and a modeling apparatus.

Conventionally, there has been known a method for manufacturing a shaped body by stacking shaping layers containing metal (for example, Patent Literatures 1 and 2). In general, the laminated modeling layers are formed by solidifying metal powder that is melted by being supplied to the focal point of the laser beam.

Japanese Unexamined Patent Application Publication No. 2003-1439 JP-A-3-146603

However, when forming a modeled body by stacking different types of modeling layers, cracks may occur due to differences in thermal expansion coefficients of the modeling layers. The occurrence of cracks reduces the strength of the modeled body. This problem has been difficult to solve even with the above prior art.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide a technique for suppressing a decrease in the strength of a shaped body in a manufacturing method of the shaped body.

The present invention has been made to solve at least part of the above problems, and can be implemented as the following modes.

(1) According to one aspect of the present invention, there is provided a method for manufacturing a shaped body by laminating shaping layers containing metal to manufacture a shaped body. The manufacturing method of this shaped body includes a first step of forming a first shaped layer on a substrate by melting and solidifying a first metal powder, and a second step of heating the first shaped layer. and a third step of forming a second modeling layer having a coefficient of thermal expansion smaller than that of the first modeling layer, wherein the second metal powder is melted and solidified to form the heated first modeling layer. and a third step of forming the second modeling layer.

According to this configuration, in the manufacturing method of the modeled body, after the first step of forming the first modeled layer on the base material, the first modeled layer is heated in the second step, and the thermal expansion is performed in the third step. A second modeling layer with a smaller modulus is formed on the heated first modeling layer to produce a shaped body. As a result, after the second modeling layer is formed, the difference in thermal contraction between the first modeling layer and the second modeling layer becomes smaller when the temperature of the modeled body drops, so that the contraction strain of the second modeling layer causes the second modeling layer to shrink. The number of cracks generated in one modeling layer can be reduced. Therefore, it is possible to suppress a decrease in the strength of the modeled body due to cracks.

(2) In the manufacturing method of the shaped body of the above aspect, in the first step, the first metal powder is melted by irradiating the first metal powder with a laser beam, and in the third step, The second metal powder may be melted by irradiating the second metal powder with a laser beam having a lower intensity than the laser beam with which the first metal powder is irradiated in the first step. According to this configuration, in the third step, the intensity of the laser beam with which the second metal powder is irradiated is made smaller than the intensity of the laser beam with which the first metal powder is irradiated in the first step. As a result, the temperature of the second modeling layer is less likely to rise, so the difference between the temperature of the first modeling layer and the temperature of the second modeling layer can be reduced when the second modeling layer is being formed. Therefore, since the difference in thermal contraction between the first modeling layer and the second modeling layer when the temperature of the modeled body drops, it is possible to suppress the reduction in the strength of the modeled body due to cracks.

(3) In the method for manufacturing a shaped body of the above aspect, the first step includes a first layer forming step of forming a first layer of the first shaping layer on the base material, and a first layer forming step of forming the first layer of the first shaping layer. A second layer forming step of forming two layers on the first layer, wherein the coefficient of thermal expansion of the second layer is larger than that of the second modeling layer and smaller than that of the first layer. and a two-layer forming step, and in the third step, the second modeling layer may be formed on the second layer. According to this configuration, in the first layer forming step of the first step, the first layer is formed on the base material, and in the second layer laminating step of the first step, the thermal expansion coefficient is formed on the first layer , and a second layer larger than the second shaping layer and smaller than the first layer. Then, in a third step, a second modeling layer is formed on the second layer. As a result, the difference in thermal contraction between the second modeling layer side of the first modeling layer and the second modeling layer can be further reduced. The number of cracks generated in one modeling layer can be further reduced. Therefore, it is possible to further suppress a decrease in the strength of the modeled body.

(4) In the manufacturing method of the shaped body of the above aspect, in the second layer forming step, the mixed powder of the first metal powder and the second metal powder is melted and solidified to form the second layer. may be formed. According to this configuration, when forming the second layer, the mixed powder of the first metal powder and the second metal powder is melted and solidified. This makes it possible to easily form the second layer whose coefficient of thermal expansion is larger than that of the second modeling layer and smaller than that of the first layer. Therefore, it is possible to easily reduce the difference in thermal contraction between the second modeling layer side of the first modeling layer and the second modeling layer, so that it is possible to easily suppress deterioration in the strength of the modeled body due to cracks.

(5) In the manufacturing method of the shaped body of the above aspect, in the second layer forming step, the mixed powder is melted so that the content of the first metal powder decreases as the thickness of the second layer increases. The second layer may be formed by solidifying. According to this configuration, when forming the second layer, the mixed powder in which the content of the first metal powder decreases as the thickness of the second layer increases is melted and solidified. As a result, the properties of the first modeling layer can gradually approach the properties of the second modeling layer from the substrate side to the second modeling layer side. Therefore, since the contraction strain of the second modeling layer when the temperature of the modeled body drops, cracks are less likely to occur, thereby further suppressing a decrease in the strength of the modeled body.

(6) According to another aspect of the present invention, there is provided a modeling apparatus for manufacturing a modeled body by laminating modeling layers containing metal. This molding apparatus includes a powder supply section that supplies a plurality of types of metal powder onto a base material, a powder heating section that heats and melts the metal powder on the base material, and a metal powder that solidifies to form a metal powder. and a modeling layer heating unit for heating the modeling layer. According to this configuration, the modeling apparatus can heat the modeling layer formed by solidifying the molten metal powder by the modeling layer heating section. As a result, when manufacturing the modeled body, the metal powder is melted and solidified on the heated modeled layer to form the modeled layer. can reduce the difference. Therefore, it is possible to reduce the number of cracks generated in the first modeling layer due to shrinkage strain of the second modeling layer, so that it is possible to suppress a decrease in the strength of the modeled body.

It should be noted that the present invention can be implemented in various aspects, for example, a modeled body manufactured by a modeled body manufacturing method, a system including a modeling device, a control method for these devices and systems, and a method for controlling these devices and systems. can be realized in the form of a computer program for executing the method for manufacturing a modeled body, a server device for distributing the computer program, a non-temporary storage medium storing the computer program, or the like.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows schematic structure of the modeling apparatus of 1st Embodiment. It is a figure explaining the manufacturing method of the modeling object with the modeling apparatus of 1st Embodiment. It is a cross-sectional photograph of a molded body of a comparative example. 4 is a cross-sectional photograph of the modeled body of the first example. It is a cross-sectional photograph of the modeled body of the second example. It is a figure explaining the time change of the surface temperature of a modeled object. It is a figure explaining the difference in the thermal contraction difference of a modeled object. FIG. 10 is a first diagram for explaining a manufacturing method of a modeled body of a comparative example; FIG. 11 is a second diagram for explaining a manufacturing method of a modeled body of a comparative example; It is a figure explaining the manufacturing method of the modeling object with the modeling apparatus of 2nd Embodiment.

<First embodiment>
FIG. 1 is a schematic diagram showing a schematic configuration of a modeling apparatus 1 according to the first embodiment. FIG. 2 is a diagram illustrating a method for manufacturing the modeled body 5 in the modeling apparatus 1 of the first embodiment. The modeling apparatus 1 includes a laser emitting section 10 , a base plate 20 , a raw material supply section 31 , a nozzle section 40 and a control section 50 . A modeled body 5 modeled by the modeling apparatus 1 of the present embodiment includes a base material 6, a first modeled layer 7, and a second modeled layer 8, as shown in FIG. For convenience of explanation, in FIGS. 1 and 2, the vertical direction is defined as the z-axis direction in the modeling apparatus 1 of the present embodiment. The direction perpendicular to the z-axis is defined as the x-axis direction, and the direction perpendicular to the z-axis and the x-axis is defined as the y-axis direction.

The laser emitting section 10 has a laser light source (not shown). The laser emission unit 10 is electrically connected to the control unit 50 and emits a laser beam Lz using a laser light source in accordance with a command output by the control unit 50 . The laser beam Lz emitted by the laser emitting section 10 is applied to the base plate 20 via the nozzle section 40 . In this embodiment, the laser light Lz is emitted from the nozzle portion 40 in the negative direction of the z-axis. The laser emitting section 10 corresponds to the "powder heating section" in the claims.

The base plate 20 is a plate-shaped member arranged in the direction in which the laser light Lz is irradiated, specifically, below the nozzle section 40 (the negative direction of the z-axis). In this embodiment, the base plate 20 is made of pre-hardened steel. The base plate 20 incorporates a heater 21 that generates heat when energized. The heater 21 is electrically connected to the controller 50 and generates heat according to commands from the controller 50 .

The raw material supply unit 31 supplies multiple types of metal powders M to the nozzle unit 40 . The raw material supply unit 31 is electrically connected to the control unit 50 and adjusts the type and amount of the metal powder M supplied to the nozzle unit 40 and the supply timing according to commands output by the control unit 50 . In this embodiment, the raw material supply section 31 is connected to a metal powder storage section (not shown). The raw material supply unit 31 supplies the metal powder M to the nozzle unit 40 together with a carrier gas such as argon gas supplied by a gas supply unit (not shown). The raw material supply section 31 corresponds to the "powder supply section" in the claims.

The nozzle section 40 includes a nozzle 41 and a drive section 42 . The nozzle 41 is arranged between the base plate 20 and the laser emitting section 10 . The nozzle 41 has a double-tube structure, and has an inner tube portion 43 and an outer tube portion 44, as shown in FIG. The inner tubular portion 43 is a tubular member formed so that its outer diameter decreases in the negative direction of the z-axis. The inner tube portion 43 is formed so that the laser beam Lz emitted from the laser emitting portion 10 passes therethrough. In this embodiment, a shielding gas G1 is supplied around the laser light Lz passing through the inner tube portion 43 so as to surround the laser light Lz. The outer tube portion 44 is a tubular member arranged outside the inner tube portion 43 . The outer tube portion 44 is formed such that its outer diameter decreases in the negative direction of the z-axis. Between the inner tube portion 43 and the outer tube portion 44, a passage 45 is formed through which the metal powder M supplied by the raw material supply portion 31 passes. The metal powder M passing through the passage 45 is supplied onto the base plate 20 together with the carrier gas (see symbol G2 in FIG. 2).

The driving part 42 is connected to the nozzle 41 . The drive unit 42 is electrically connected to the control unit 50 and generates driving force for driving the nozzles 41 according to commands from the control unit 50 . In this embodiment, the nozzle 41 is provided movably in any of the z-axis direction, the x-axis direction, and the y-axis direction with respect to the base plate 20 . Thereby, the modeled body 5 can be formed at an arbitrary location on the surface 20 a of the base plate 20 .

The control unit 50 is a computer including a ROM, a RAM, and a CPU. The control unit 50 is electrically connected to each of the laser emission unit 10, the raw material supply unit 31, and the driving unit 42, and controls these operations according to a pre-input computer program. do. Specifically, the control unit 50 controls the emission timing of the laser light Lz emitted from the laser emission unit 10 and the intensity of the laser light Lz. The controller 50 controls the timing and amount of heat generated by the heater 21 of the base plate 20 . The control unit 50 controls the type, supply amount, supply timing, and the like of the metal powder supplied by the raw material supply unit 31 . The control unit 50 controls movement of the nozzle 41 by the drive unit 42 .

Next, a method for manufacturing the modeled body 5 of this embodiment will be described. The manufacturing method of the modeled body 5 of this embodiment is, for example, a manufacturing method using a directional energy deposition method (deposition method). In the directional energy deposition method, the metal powder M melted by the laser light Lz is deposited on the substrate 6 by supplying the metal powder M with the carrier gas G2 to the focal point of the laser light Lz irradiated on the base plate 20. to form a shaped body 5 of arbitrary shape. The base material 6 may be a member manufactured by a method different from the manufacturing method of the shaped body 5, or may be a pre-shaped body formed from metal powder by the directional energy deposition method described above. In this embodiment, the base material 6 is made of maraging steel. Note that the method of manufacturing the modeled body 5 is not limited to the directional energy deposition method. Any method may be used as long as it can form the body 5 .

First, the first modeling layer 7 is formed on the surface 60 of the base material 6 placed on the base plate 20 (first step). The control unit 50 causes the laser emitting unit 10 to emit the laser beam Lz toward the surface 60 of the base material 6, and the raw material supply unit 31 controls the portion of the surface 60 of the base material 6 irradiated with the laser beam Lz. , the first metal powder, which is the material of the first modeling layer 7, is supplied. In this embodiment, high-speed tool steel with a coefficient of thermal expansion of 11.9×10 ⁻⁶ (1/° C.) is used as the first metal. The high speed tool steel powder is melted by the energy of the laser light Lz and then solidified on the surface 60 of the base material 6 . Thereby, the first modeling layer 7 is formed on the surface 60 of the base material 6 .

Next, while heating the first modeling layer 7 (second step), the second modeling layer 8 is formed on the surface 70 of the first modeling layer 7 (third step). The controller 50 supplies power to the heater 21 to generate heat. Since the heat generated by the heater 21 is transmitted to the first modeling layer 7 via the base plate 20 and the base material 6 (see the dotted arrow H1 in the figure), the temperature of the first modeling layer 7 rises. In the present embodiment, the controller 50 supplies power to the heater 21 so that the temperature of the first modeling layer 7 reaches 200.degree.

While the first modeling layer 7 is at 200° C., the control unit 50 controls the raw material supply unit 31 to supply the second metal powder, which is the material of the second modeling layer 8, to the laser beam Lz. In this embodiment, maraging steel with a thermal expansion coefficient of 10.1×10 ⁻⁶ (1/° C.) is used as the second metal. In the present embodiment, when forming the second modeling layer 8 , the control unit 50 controls the laser emitting unit 10 to emit the laser beam Lz having a lower intensity than the laser beam Lz used when forming the first modeling layer 7 . 1 The surface 70 of the shaping layer 7 is irradiated. The control unit 50 supplies maraging steel powder to the portion of the surface 70 of the first modeling layer 7 irradiated with the laser beam Lz by the raw material supply unit 31 . The powder of the maraging steel is melted by the energy of the laser light Lz to form a melt pool 80 of the maraging steel on the surface 70 of the first modeling layer 7 . By solidifying the melt pool 80 of the maraging steel, the second modeling layer 8 is formed on the surface 70 of the first modeling layer 7, and the shaped body 5 is manufactured.

Next, the effect of the manufacturing method of the modeled body 5 of this embodiment will be described. First, the state of the shaped body manufactured by each of the three shaped body manufacturing methods with different conditions is evaluated. Specifically, for a model body formed by laminating a substrate, a first modeling layer, and a second modeling layer on a base plate, the first modeling layer when forming the second modeling layer Compare the cross sections of the shaped bodies with different temperature conditions. In each of the three manufacturing methods of the shaped bodies, a laser beam with an output of 750 W was supplied with a metal powder at a supply rate of 0.08 g/s (carrier gas flow rate of 25 L/min) by a directed energy deposition method. , to form a cuboid shaped body.

FIG. 3 is a cross-sectional photograph of a molded body A5 of a comparative example. FIG. 3 shows a modeled body A5 formed on the base plate BP20. The modeled body A5 includes a base material A6, a first modeled layer A7, and a second modeled layer A8. In the manufacturing method of the comparative example for manufacturing the modeled body A5, the temperature of the first modeled layer A7 is not adjusted when the second modeled layer A8 is formed. As shown in FIG. 3, two cracks Cr1 can be confirmed in the first model layer A7 of the model A5.

FIG. 4 is a cross-sectional photograph of the molded body B5 of the first example. FIG. 4 shows a modeled body B5 formed on the base plate BP20. The modeled body B5 includes a base material B6, a first modeled layer B7, and a second modeled layer B8. In the manufacturing method of the first embodiment for manufacturing the modeled body B5, the temperature of the first modeled layer B7 is maintained at 100° C. when the second modeled layer B8 is formed. As shown in FIG. 4, cracks Cr2 are formed in the first modeling layer B7 of the modeled body B5, and it is confirmed that the number and size of the cracks are smaller than those of the modeled body A5 of the comparative example. was done.

FIG. 5 is a cross-sectional photograph of the molded body C5 of the second example. FIG. 5 shows a modeled body C5 formed on the base plate BP20. The modeled body C5 includes a base material C6, a first modeled layer C7, and a second modeled layer C8. In the manufacturing method of the second embodiment for manufacturing the modeled body C5, the temperature of the first modeled layer C7 is maintained at 200° C. when the second modeled layer C8 is formed. As shown in FIG. 5, no cracks as seen in the cross-sectional photographs of FIGS. 3 and 4 were found in the first modeling layer C7.

Next, the thermal contraction difference between the first modeling layer and the second modeling layer in each of the shaped bodies shown in FIGS. 3 to 5 will be described. The difference in thermal contraction between the first modeling layer and the second modeling layer is the temperature when the formation of the second modeling layer is completed and the temperature when a certain time has passed since the formation of the second modeling layer is completed. is obtained from the amount of thermal shrinkage of each of the first modeling layer and the second modeling layer. The thermal contraction amount of the modeling layer is calculated using the following formula (1).
ΔL=α×(T1−T2)×L (1)
ΔL: Thermal contraction amount (μm)
α: Thermal expansion coefficient (×10 ⁻⁶ /° C.)
T1: temperature (°C) when the formation of the second modeling layer is completed
T2: Temperature (°C) after a certain period of time has elapsed since the formation of the second modeling layer was completed
L: length of one side of the cuboid shaped body (mm)

FIG. 6 is a diagram for explaining temporal changes in the surface temperature of the modeled body. FIG. 6 is a diagram showing changes over time in the surface temperature of the second modeling layer, showing changes over time in temperature from the end of formation of the second modeling layer (time 0 minutes in FIG. 6) to 13 minutes. ing. In obtaining the difference in thermal contraction between the first modeling layer and the second modeling layer, first, the temperature T1 of the second modeling layer when the formation of the second modeling layer is completed is calculated. The following temperature obtained by extrapolating the temperature T1 when the formation of the second modeling layer is completed using the temperature change data shown in FIG. 6 is the temperature T1 of the second modeling layer.
Comparative example (no temperature adjustment): 217°C
First example (temperature 100°C): 152°C
Second example (temperature 200°C): 127°C

As the temperature T2 of the second modeling layer when a certain period of time has elapsed since the formation of the second modeling layer was completed, the temperature 3 minutes after the completion of the formation of the second modeling layer shown in FIG. 6 was used. As the temperature T2 of the first modeling layer, the following temperatures three minutes after the completion of the formation of the second modeling layer were used.
Comparative example: 41°C
First example: 102°C
Second example: 201°C

FIG. 7 is a diagram for explaining the difference in thermal contraction difference between shaped bodies. FIG. 7 is obtained for each of the shaped body A5 of the comparative example, the shaped body B5 of the first example, and the shaped body C5 of the second example using the temperature change data shown in FIG. It shows the difference in heat shrinkage. As shown in FIG. 7, the molded body A5 of the comparative example in which two relatively large cracks Cr1 were confirmed had a thermal shrinkage difference of 1.55 μm. On the other hand, the molded body A5 of the first example, which has smaller number and size of cracks than the molded body A5 of the comparative example, has a thermal shrinkage difference of 0.90 μm, which is smaller than the thermal shrinkage difference of the molded body A5 of the comparative example. It became clear. In addition, it was found that the thermal shrinkage difference was 0.29 μm in the modeled body C5 of the second example in which no cracks were observed. That is, from the evaluation results of the first example and the second example, it is clear that the number and size of cracks can be reduced by heating the first modeling layer when forming the second modeling layer. became. In particular, under the conditions of the present embodiment (rectangular parallelepiped modeled body, first modeled layer: high-speed tool steel, second modeled layer: maraging steel), the difference in heat shrinkage between the first modeled layer and the second modeled layer is It was confirmed that by heating the first modeling layer to 200° C. so that the thickness becomes 0.3 μm or less (second example), the occurrence of cracks in the first modeling layer can be suppressed.

FIG. 8 is the first diagram for explaining the manufacturing method of the modeled body A5 of the comparative example. In the modeled body A5 of the comparative example, as described above, when the second modeled layer A8 is formed, the temperature of the first modeled layer A7 is not adjusted, so the temperature is relatively low. Therefore, the second modeling layer A8 heated to a high temperature by the energy of the laser light is formed on the first modeling layer A7 having a relatively low temperature.

FIG. 9 is a second diagram for explaining the manufacturing method of the modeled body A5 of the comparative example, and shows the modeled body A5 after forming the second modeling layer A8. After the second modeling layer A8 is formed and the modeling body A5 is completed, the temperature of the entire modeling body A5 drops, so the second modeling layer A8, which is at a high temperature, shrinks relatively greatly due to the temperature change (Fig. 9 white arrow F1). On the other hand, since the first modeling layer A7 adjacent to the second modeling layer A8 was at a relatively low temperature, the amount of shrinkage due to temperature change was relatively small. For this reason, stress due to contraction strain of the second modeling layer A8 is generated, and many cracks Cr1 are generated in the first modeling layer A7. If the crack Cr1 occurs, the strength of the modeled body A5 may be reduced and the modeled body A5 may be damaged.

According to the method for manufacturing the modeled body 5 of the present embodiment described above, after the first step of forming the first modeled layer 7 on the base material 6, the first modeled layer 7 is heated in the second step. , in the third step, a second modeling layer 8 having a small coefficient of thermal expansion is formed on the heated first modeling layer 7 to manufacture the shaped body 5 . As a result, when the temperature of the modeled body 5 decreases after the second modeled layer 8 is formed, the difference in thermal contraction between the first modeled layer 7 and the second modeled layer 8 becomes smaller. It is possible to reduce the number of cracks generated in the first modeling layer 7 due to the shrinkage strain of . Therefore, it is possible to suppress a decrease in the strength of the modeled body 5 due to cracks.

Further, according to the method for manufacturing the shaped body 5 of the present embodiment, in the third step, the intensity of the laser beam Lz with which the powder of the maraging steel is irradiated is adjusted to the intensity of the laser beam Lz with which the powder of the high-speed tool steel is irradiated in the first step. be smaller than the intensity of the laser beam Lz. As a result, the temperature of the second modeling layer 8 is less likely to reach a high temperature, so that the difference between the temperature of the first modeling layer 7 and the temperature of the second modeling layer 8 during the formation of the second modeling layer 8 can be reduced. can. Therefore, since the difference in thermal contraction between the first modeling layer 7 and the second modeling layer 8 when the temperature of the modeled body 5 is lowered becomes small, it is possible to suppress the reduction in the strength of the modeled body 5 due to cracks.

Further, according to the modeling apparatus 1 of the present embodiment, the heater 21 can heat the first modeling layer 7 formed by solidifying the molten high-speed tool steel powder. As a result, when manufacturing the modeled body 5 , the maraging steel powder is melted and solidified on the heated first modeled layer 7 to form the second modeled layer 8 . It is possible to reduce the difference in thermal contraction caused by the difference in thermal expansion coefficient between the second shaping layer 8 and the second modeling layer 8 . Therefore, since the number of cracks generated in the first modeling layer 7 due to the shrinkage strain of the second modeling layer 8 can be reduced, the reduction in the strength of the modeled body 5 can be suppressed.

<Second embodiment>
10A and 10B are diagrams for explaining a method of manufacturing a modeled object in the modeling apparatus of the second embodiment. Compared to the method of manufacturing the shaped body of the first embodiment (FIG. 2), the method of manufacturing the shaped body of the second embodiment changes the characteristics of the first shaped layer according to the thickness of the first shaped layer. is different.

The modeling apparatus 2 of this embodiment includes a laser emitting section 10 , a base plate 20 , a raw material supply section 32 , a nozzle section 40 and a control section 50 .

The raw material supply unit 32 supplies multiple types of metal powders M to the nozzle unit 40 . The raw material supply unit 32 is electrically connected to the control unit 50 and adjusts the type, amount, and supply timing of the metal powder M supplied to the nozzle unit 40 according to commands output by the control unit 50 . In the present embodiment, the raw material supply unit 32 is capable of supplying mixed powder obtained by mixing high-speed tool steel powder and maraging steel powder to the nozzle unit 40 in accordance with a command from the control unit 50. . The raw material supply section 32 corresponds to the "powder supply section" in the claims.

Next, a method for manufacturing the modeled body 5 of this embodiment will be described. In the method for manufacturing the modeled body 5 of the present embodiment, in the first step of forming the first modeled layer 7, first, the first layer 71 of the first modeled layer 7 on the side of the substrate 6 is formed (first 1 layer forming step). The control unit 50 controls the laser emission unit 10 to irradiate the surface 60 of the base material 6 placed on the surface 20a of the base plate 20 with the laser beam Lz, and controls the raw material supply unit 31 to produce a high Supply speed tool steel powder. Thereby, a first layer 71 made of high-speed tool steel is formed on the surface 60 of the substrate 6 .

Next, a second layer 72 of the first modeling layer 7, which is on the second modeling layer 8 side, is formed (second layer forming step). The control unit 50 controls the laser emitting unit 10 to irradiate the surface of the first layer 71 with the laser beam Lz, and controls the raw material supply unit 31 to generate high-speed tool steel powder and maraging steel powder. A mixed powder is supplied. In this embodiment, when forming the second layer 72, first, a mixed powder having a higher proportion of the high speed tool steel powder than the maraging steel powder is supplied to form part of the second layer 72. do. After that, as the thickness of the second layer 72 increases, a mixed powder is supplied in which the proportion of the high-speed tool steel powder in the mixed powder is decreased and the proportion of the maraging steel powder is increased. As a result, the second layer 72 has a portion close to the characteristics of the first layer 71 on the first layer 71 side, and a portion close to the characteristics of the second modeling layer 8 on the second layer 72 side. .

Next, while heating the first modeling layer 7 with the heater 21 , the second modeling layer 8 is formed on the surface of the second layer 72 as in the first embodiment. Thereby, the second modeling layer 8 is formed on the surface 70 of the first modeling layer 7, and the modeled body 5 is manufactured.

According to the method for manufacturing the modeled body 5 of the present embodiment described above, the first layer 71 is formed on the base material 6 in the first layer forming step of the first step, and the second layer forming step of the first step is performed. In the process, a second layer 72 having a thermal expansion coefficient larger than that of the second shaping layer 8 and smaller than that of the first layer 71 is formed on the first layer 71 . After that, in the third step, the second shaping layer 8 is formed on the second layer 72 . As a result, the difference in thermal contraction between the second modeling layer side of the first modeling layer 7 and the second modeling layer 8 can be further reduced, so that when the temperature of the modeled body 5 is lowered, the second modeling layer is The number of cracks generated in the first modeling layer 7 due to the shrinkage strain of 8 can be further reduced. Therefore, it is possible to further suppress a decrease in the strength of the modeled body 5 due to cracks.

Further, according to the method for manufacturing the shaped body 5 of the present embodiment, when forming the second layer 72, the mixed powder of the high-speed tool steel powder and the maraging steel powder is melted and solidified. Thereby, the second layer 72 having a coefficient of thermal expansion larger than that of the second shaping layer 8 and smaller than that of the first layer 71 can be easily formed. Therefore, the difference in thermal contraction between the second modeling layer side of the first modeling layer 7 and the second modeling layer 8 can be easily reduced, so that the reduction in strength of the modeled body 5 due to cracks can be easily suppressed. can be done.

Further, according to the method for manufacturing the shaped body 5 of the present embodiment, when forming the second layer 72, the mixed powder in which the content of the high-speed tool steel powder decreases as the thickness of the second layer 72 increases. is melted and solidified. As a result, the properties of the first modeling layer 7 can gradually approach the properties of the second modeling layer 8 from the substrate 6 side to the second modeling layer 8 side. Therefore, the stress due to the contraction strain of the second modeling layer 8 when the temperature of the modeling body 5 is lowered can be easily relaxed, so cracks are less likely to occur, and the strength reduction of the modeling body 5 can be further suppressed.

<Modification of this embodiment>
The present invention is not limited to the above-described embodiments, and can be implemented in various aspects without departing from the scope of the invention. For example, the following modifications are possible.

[Modification 1]
In the first embodiment, when the second modeling layer 8 is formed, the first modeling layer 7 is heated together with the substrate 6 by the heater 21 as the "modeling layer heating unit", but only the first modeling layer 7 is heated. may be In this case, for example, only the first modeling layer 7 may be heated by a heat gun capable of heating, and the heating method is not limited to these.

[Modification 2]
In the above-described embodiment, while the first modeling layer 7 is heated in the "second step", the second modeling layer 8 is formed in the "third step". It is not limited to this. When forming the second modeling layer 8, it is sufficient that the temperature of the first modeling layer 7 is elevated. The first shaping layer 7 may be heated.

[Modification 3]
In the above-described embodiment, the high-speed tool steel powder forming the first modeling layer 7 and the maraging steel powder forming the second modeling layer 8 are each heated by the laser beam Lz. The method of heating the metal powder is not limited to this. Further, the intensity of the laser light Lz may be the same in the first step and the third step, or may be higher in the third step than in the first step.

[Modification 4]
In the second embodiment, when forming the second layer 72, mixed powder of high-speed tool steel powder and maraging steel powder is supplied. When forming the second layer 72 , metal powder having a thermal expansion coefficient larger than that of the second modeling layer 8 and smaller than that of the first layer 71 may be supplied.

[Modification 5]
In the second embodiment, when the second layer 72 is formed, mixed powder in which the content of the high-speed tool steel powder decreases as the thickness of the second layer 72 increases is melted and solidified. For example, the second layer 72 may be formed by melting and solidifying a mixed powder containing 50% high-speed tool steel powder and 50% maraging steel powder.

[Modification 6]
In the above-described embodiments, the base material 6 is made of maraging steel, which is a ferrous material. The base material 6 may be made of another iron-based material, or may be made of a material different from the iron-based material.

[Modification 7]
In the above-described embodiment, the modeled body 5 includes the base material 6 , the first modeled layer 7 , and the second modeled layer 8 . The configuration of the modeled body 5 is not limited to this. The substrate 6 may be omitted, and the first modeling layer 7 and the second modeling layer 8 may be laminated on the base plate 20 . Further, the number of modeling layers included in the modeling body 5 is not limited to two, and may be three or more. In this case, it is sufficient that the modeling layer on which the molten metal powder is placed is heated to a high temperature. Further, the base material 6 may be a member manufactured by a method different from the manufacturing method of the shaped body 5, or a pre-shaped body formed from metal powder by a directional energy deposition method. layers may be laminated.

[Modification 8]
In the above-described embodiment, the manufacturing method of the shaped body is the manufacturing method by the directional energy deposition method, but the manufacturing method of the shaped body is not limited to this. Any method may be used as long as it forms the second modeling layer on the surface of the substrate, and then laminates the first modeling layer on the second modeling layer to model the modeled body.

[Modification 9]
In the above-described embodiment, in the third step, the intensity of the laser beam Lz irradiated to the powder of the maraging steel is made smaller than the intensity of the laser beam Lz irradiated to the powder of the high-speed tool steel in the first step. . Furthermore, when the second shaping layer 8 is formed, even if the supply amount of the maraging steel powder is reduced and the shaping speed of the second shaping layer 8 is suppressed, the occurrence of cracks can be suppressed.

[Modification 10]
As described in FIGS. 3 to 7 of the first embodiment, by setting the temperature of the first modeling layer C7 to 200° C. when forming the second modeling layer C8 (second example), the first It was confirmed that it is possible to suppress the occurrence of cracks in the modeling layer C7. On the other hand, as in the first embodiment in which the temperature of the first modeling layer B7 when forming the second modeling layer B8 was set to 100° C., the temperature of the first modeling layer was kept constant when the second modeling layer was formed. By heating to a certain degree, the difference in thermal shrinkage becomes smaller than that of the shaped body of the comparative example (see FIG. 7). As a result, the number and size of cracks can be made smaller than those of the molded body A5 of the comparative example. That is, by heating the first modeling layer when forming the second modeling layer, the difference in thermal contraction between the first modeling layer and the second modeling layer is reduced, so the number and size of cracks are reduced. A decrease in the strength of the shaped body can be suppressed.

The present aspect has been described above based on the embodiments and modifications, but the above-described embodiments are intended to facilitate understanding of the present aspect, and do not limit the present aspect. This aspect may be modified and modified without departing from its spirit and scope of the claims, and this aspect includes equivalents thereof. Also, if the technical features are not described as essential in this specification, they can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 1, 2... Modeling apparatus 5... Modeling object 6... Base material 7... 1st modeling layer 8... 2nd modeling layer 10... Laser emission part 21... Heater 31, 32... Raw material supply part 71... 1st layer 72... 2nd Layer Lz... Laser beam M... Metal powder

Claims (6)

A method for manufacturing a modeled body by laminating modeling layers containing metal, comprising:
a first step of forming a first modeling layer on the substrate by melting and solidifying the first metal powder;
a second step of heating the first modeling layer;
A third step of forming a second modeling layer having a coefficient of thermal expansion smaller than that of the first modeling layer, wherein a second metal powder is melted and solidified to form a and a third step of forming the second modeling layer.
A method for manufacturing a shaped body. A method for manufacturing a shaped body according to claim 1,
In the first step, the first metal powder is melted by irradiating the first metal powder with a laser beam,
In the third step, the second metal powder is irradiated with a laser beam having a lower intensity than the laser beam with which the first metal powder is irradiated in the first step. melt,
A method for manufacturing a shaped body. A method for manufacturing a shaped body according to claim 1 or claim 2,
The first step is
a first layer forming step of forming a first layer of the first modeling layer on the base material;
A second layer forming step of forming a second layer of the first modeling layer on the first layer, wherein a coefficient of thermal expansion is larger than that of the second modeling layer and smaller than that of the first layer. a second layer forming step of forming a second layer,
In the third step, the second modeling layer is formed on the second layer,
A method for manufacturing a shaped body. A method for manufacturing a shaped body according to claim 3,
In the second layer forming step, the second layer is formed by melting and solidifying a mixed powder of the first metal powder and the second metal powder.
A method for manufacturing a shaped body. A method for manufacturing a shaped body according to claim 4,
In the second layer forming step, the second layer is formed by melting and solidifying the mixed powder in which the content of the first metal powder decreases as the thickness of the second layer increases.
A method for manufacturing a shaped body. A modeling apparatus for manufacturing a modeled body by stacking modeling layers containing metal,
a powder supply unit that supplies a plurality of types of metal powders onto a substrate;
a powder heating unit that heats and melts the metal powder on the substrate;
a modeling layer heating unit that heats a modeling layer formed by solidifying the molten metal powder;
molding device.

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